<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * Analyzes US-ASCII characters.
 *
 * @package    Swift
 * @subpackage Encoder
 * @author     Chris Corbyn
 */
class Swift_CharacterReader_UsAsciiReader implements Swift_CharacterReader
{
	/**
	 * Returns the complete character map.
	 *
	 * @param string $string
	 * @param integer $startOffset
	 * @param array $currentMap
	 * @param string $ignoredChars
	 *
	 * @return integer
	 */
	public function getCharPositions($string, $startOffset, &$currentMap, &$ignoredChars)
	{
		$strlen = strlen($string);
		$ignoredChars = '';
		for ($i = 0; $i < $strlen; ++$i) {
			if ($string[$i] > "\x07F") { // Invalid char
				$currentMap[$i + $startOffset] = $string[$i];
			}
		}

		return $strlen;
	}

	/**
	 * Returns mapType
	 *
	 * @return integer mapType
	 */
	public function getMapType()
	{
		return self::MAP_TYPE_INVALID;
	}

	/**
	 * Returns an integer which specifies how many more bytes to read.
	 *
	 * A positive integer indicates the number of more bytes to fetch before invoking
	 * this method again.
	 * A value of zero means this is already a valid character.
	 * A value of -1 means this cannot possibly be a valid character.
	 *
	 * @param string $bytes
	 * @param integer $size
	 *
	 * @return integer
	 */
	public function validateByteSequence($bytes, $size)
	{
		$byte = reset($bytes);
		if (1 == count($bytes) && $byte >= 0x00 && $byte <= 0x7F) {
			return 0;
		} else {
			return -1;
		}
	}

	/**
	 * Returns the number of bytes which should be read to start each character.
	 *
	 * @return integer
	 */
	public function getInitialByteSize()
	{
		return 1;
	}
}
